Difference between revisions of "ISO 19115:2003 Geographic information - Metadata"
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Revision as of 05:50, 19 May 2017
Overview of ISO 19115:2003
|Full name||ISO 19115:2003, Geographic information -- Metadata|
|Version||Edition 1 (withdrawn, replaced by ISO 19115-1:2014)|
|Corrigenda||ISO 19115:2003/Cor 1 2006, Geographic information – Metadata – Corrigendum 1|
|Published by||ISO/TC 211|
|Online overview||Not available|
|Type of standard||ISO International Standard |
|Application||The standard specifies how to document metadata, which includes information on data quality, lineage, etc.|
|Conformance classes||Maximum occurrence |
User-defined extension metadata
ISO 19115:2003 defines the schema required for describing geographic information and services. It provides information about the identification, the extent, the quality, the spatial and temporal schema, spatial reference, and distribution of digital geographic data.
ISO 19115:2003 is applicable to:
- the cataloguing of datasets, clearinghouse activities, and the full description of datasets;
- geographic datasets, dataset series, and individual geographic features and feature properties.
ISO 19115:2003 defines:
- mandatory and conditional metadata sections, metadata entities, and metadata elements;
- the minimum set of metadata required to serve the full range of metadata applications (data discovery, determining data fitness for use, data access, data transfer, and use of digital data);
- optional metadata elements – to allow for a more extensive standard description of geographic data, if required;
- a method for extending metadata to fit specialized needs.
Though ISO 19115:2003 is applicable to digital data, its principles can be extended to many other forms of geographic data such as maps, charts, and textual documents as well as non-geographic data.
NOTE: Certain mandatory metadata elements may not apply to these other forms of data.
Unfortunately, there is a perception that metadata are difficult and tedious to capture, and of no real value. Indeed, some suggest that with the power of search engines, metadata are actually unnecessary – which betrays a poor understanding of what metadata are. The claim is that the search engines are so good that they can find everything, but metadata often includes information that would otherwise not be available – even to a search engine.
ISO 19115-1:2014 is a revision of ISO 19115:2003 and hence will replace it. ISO 19115:2003 will probably remain available through ISO (as withdrawn rather than deleted), because of the masses of legacy metadata already in the ISO 19115:2003 format. If one uses geospatial data from other organisations, then one will probably have to implement ISO 19115:2003 to be able to read and process the metadata of such geospatial datasets. However, ISO 19115:2003 has been implemented directly in many GISs, both proprietary and open source, so it is likely that one’s system already supports ISO 19115:2003. Nevertheless, it is still necessary to understand the standard to be able to interpret the metadata.
On the other hand, if one is starting from scratch with the capturing of metadata for geospatial datasets that one is producing, then it would be best to start with ISO 19115-1:2014, which has now been published and is summarised below.
ISO 19115 is used widely and has been implemented directly in many different GISs, both proprietary and open source. There are also stand-alone and/or web-based metadata editors available that support ISO 19115. To varying extents, these GISs and editors can automate the capture of metadata.
These GISs and editors also typically support Content Standard for Digital Geospatial Metadata (CSDGM) from the Federal Geographic Data Committee (FGDC) of the U.S. and other metadata standards, so care must be taken to select the correct standard before capturing metadata. CSDGM is largely similar to ISO 19115 and there is a crosswalk between the two standards. Because ISO 19115 is generally encoded and ISO 15836 (Dublin Core) is primarily free text, it is relatively easy to convert from ISO 19115 to ISO 15836, but not the other way around.
Similar standards are:
- ISO 19115-2:2009, Geographic information – Metadata – Part 2: Extensions for imagery and gridded data
- ISO 19119:2005/Amd 1:2008, Extensions of the service metadata model
- CSDGM, a predecessor of ISO 19115 (also known as FGDC, the committee responsible for it)
While ISO 19115:2003 was published in May 2003, a substantial corrigendum (of 33 pages) for ISO 19115:2003 was published in July 2006. When one purchases ISO 19115:2003, the corrigendum should be included at the beginning of the document.
ISO 19115:2003 allows metadata to be defined for collections of datasets (such as in a series, for a particular data capturing platform and/or sensor, or for an initiative), individual datasets and parts of a dataset, even down to individual features and attributes. The standard includes a comprehensive dataset metadata profile with hundreds of metadata elements. There are 14 packages of metadata:
- Metadata entity set information, MD_Metadata
- Identification information, MD_Identification
- Constraint information, MD_Constraints
- Data quality information, DQ_DataQuality
- Maintenance information, MD_MaintenanceInformation
- Spatial representation information, MD_SpatialRepresentation
- Reference system information, MD_ReferenceSystem
- Content information, MD_ContentInformation
- Portrayal catalogue information, MD_PortrayalCatalogueReference
- Distribution information, MD_Distribution
- Metadata extension information, MD_MetadataExtensionInformation
- Application schema information, MD_ApplicationSchemaInformation
- Extent information, EX_Extent
- Citation and responsible party information, CI_Citation & CI_ResponsibleParty
ISO 19115:2003 defined a core metadata profile, primarily for cataloguing purposes, but it is what most users are likely to have implemented, possibly with a few additions. Nominally, this core profile has only 22 metadata elements, as shown in Table 11.3, but in practice this expands into many more metadata elements. The draft African profile of ISO 19115:2003 followed this approach. It was compiled in 2007 for the CODIST-Geo Working Group on Standards: CODIST is the Committee on Development Information, Science and Technology, established to inform the United Nations Economic Commission for Africa (UN ECA) on development challenges, and CODIST-Geo is the CODIST Sub-committee for Geo-information. Unfortunately, funding was not available to complete and publish the African profile of ISO 19115:2003.
|Dataset title (M)||(MD_Metadata > MD_DataIdentification.citation > CI_Citation.title)|
|Dataset reference date (M)||(MD_Metadata > MD_DataIdentification.citation > CI_Citation.date)|
|Dataset responsible party (O)||(MD_Metadata > MD_DataIdentification.pointOfContact > CI_ResponsibleParty)|
|Geographic location of the dataset (by four coordinates or by geographic identifier) (C)||(MD_Metadata > MD_DataIdentification.extent > EX_Extent > EX_GeographicExtent > EX_GeographicBoundingBox or EX_GeographicDescription)|
|Dataset language (M)||(MD_Metadata > MD_DataIdentification.language)|
|Dataset character set (C)||(MD_Metadata > MD_DataIdentification.characterSet)|
|Dataset topic category (M)||(MD_Metadata > MD_DataIdentification.topicCategory)|
|Spatial resolution of the dataset (O)||(MD_Metadata > MD_DataIdentification.spatialResolution > MD_Resolution.equivalentScale or MD_Resolution.distance)|
|Abstract describing the dataset (M)||(MD_Metadata > MD_DataIdentification.abstract)|
|Distribution format (O)||(MD_Metadata > MD_Distribution > MD_Format.name and MD_Format.version)|
|Additional extent information for the dataset (vertical and temporal) (O)||(MD_Metadata > MD_DataIdentification.extent > EX_Extent > EX_TemporalExtent or EX_VerticalExtent)|
|Spatial representation type (O)||(MD_Metadata > MD_DataIdentification.spatialRepresentationType)|
|Reference system (O)||(MD_Metadata > MD_ReferenceSystem)|
|Lineage (O)||(MD_Metadata > DQ_DataQuality.lineage > LI_Lineage)|
|On-line resource (O)||(MD_Metadata > MD_Distribution > MD_DigitalTransferOption.onLine > CI_OnlineResource)|
|Metadata file identifier (O)||(MD_Metadata.fileIdentifier)|
|Metadata standard name (O)||(MD_Metadata.metadataStandardName)|
|Metadata standard version (O)||(MD_Metadata.metadataStandardVersion)|
|Metadata language (C)||(MD_Metadata.language)|
|Metadata character set (C)||(MD_Metadata.characterSet)|
|Metadata point of contact (M)||(MD_Metadata.contact > CI_ResponsibleParty)|
|Metadata date stamp (M)||(MD_Metadata.dateStamp)|
NOTE: in the left-hand column, (M) is Mandatory, i.e. this element shall always be included in the metadata to conform to the profile; (C) is Conditional, i.e. this element shall be included in the metadata, only if a certain condition has been met; and (O) is Optional, i.e. this element may be included, at the discretion of the person or organisation compiling the metadata.
ISO19115:2003 provides in Clause 6, an overview of the metadata catered for by the standard. The detailed metadata are described in Annex A using UML diagrams and in Annex B using a data dictionary, that is, a table with detailed text descriptions of the metadata elements, the metadata entities (logical groups of metadata elements) and the code lists. The tables in Annex B are formatted according to ISO/IEC 11179, Information technology – Metadata registries (MDR). The data dictionary is probably easier for most users to read, but the UML diagrams show how all the metadata packages, entities and elements are structured. Annex C of ISO 19115:2003 provides rules for how extensions to, and profiles of, the standard may be created and Annex F describes a recommended methodology for creating metadata extensions. Annex E provides the comprehensive dataset metadata application profile, which is not simply everything defined in Annexes A and B. It consists of the classes, attributes and relationships needed for the metadata for a general purpose dataset, excluding the service-related classes, for example. Annexes G and H present guidelines on implementing the standard and Annex I contains some examples of metadata conforming to the standard. Finally, Annex J describes how ISO 19115:2003 provides multilingual support for free text metadata elements, which allows for text in multiple languages and character sets to be included in the same metadata file. With the variety of languages used across Africa, this is clearly an advantage for using ISO 19115:2003 in Africa.
- ISO 19115-2:2009 Geographic information - Metadata - Part 2: Extensions for imagery and gridded data
- ISO 19131:2007 Geographic information - Data product specifications
- ISO/TS 19139:2007 Geographic information - Metadata - XML schema implementation
- ISO/TS 19139-2:2012 Geographic information - Metadata - XML schema implementation - Part 2: Extensions for imagery and gridded data
- ISO 15836:2009 Information and documentation - The Dublin Core metadata element set